The present invention relates to an exchange. Particularly, the present invention relates to an office data management system that can be operated and managed in common by each of exchanges in a switching network. The present invention also is to provide a system for assigning personal numbers to subscribers. Moreover, the present invention relates to a same subscriber number migrating system where the same subscriber number can be used even if a subscriber is transferred to another exchange.
Conventionally, when a subscriber is accommodated in a different exchange, its area code and its subscriber number are changed. In the conventional open numbering plan made by area codes and subscriber numbers, where a subscriber is relocated a station with a different area code, its area code is necessarily changed, so that the same station cannot manage and operate plural area codes. Moreover, in the closed numbering system made by only subscriber numbers, the subscriber can be basically relocated with the same subscriber number. However, when subscriber numbers are accommodated at random, which station a subscriber is accommodated in cannot be specified if the subscriber number is checked up to the last digit. This system complicates the numbering plan. In the worst cases, a change in one subscriber may require changing the office data in all the exchanges within a network. This results in increased working costs. Hence, since large-scaled networks employ the open numbering plan or partially the closed numbering plan, it has been substantially impossible to migrate a subscriber with the same number. Moreover, since each exchange managing subscriber numbers manages its numbering plan, even one subscriber's relocation causes requires changing office data in two exchanges or more, thus causing troublesome tasks.
As described above, the conventional exchange involves in always changing the subscriber number when a subscriber is relocated to another exchange. Changes in the subscriber number make the company's business activity and private life very inconvenient. Recently, there have been strong demands for the necessity of personal telephone numbers. For that reason, a switching system is required such that can realize uses of personal telephone numbers and facilitate the operation and management.
The system where plural distributed node exchanges configures a network so as to operate as one exchange is proposed (refer to Japanese Patent Application (Tokugan-Hei) No. 11263/1997).